The present invention relates to a rapid and efficient method for the purification of yeast expressed recombinant pre-S-Hepatitis B surface antigen (HBsAg).
The hepatitis B pre-S region of the surface antigen has been identified as the receptor site on the virus which binds to hepatocytes prior to entry of the hepatitis B virus into the cell, Valenzuela et al., Bio/Technology 3:317-320 (1985). The pre-S region binds to polymerized serum albumin believed to be associated with the cell membrane of the hepatocytes. Consequently, pre-S containing, recombinant derived, antigens have been suggested as antigens that could induce antibody that would block attachment of the hepatitis B virus to susceptible host cells. Hepatitis B virus pre-S containing surface antigen has been isolated from infected human plasma, Neurath and Strick, Arch. Virol. 60:79-81 (1979) and has recently been obtained using standard recombinant techniques as described by Valenzuela, supra. Indeed, Neurath and Strick were able to isolate a minor population of HBsAg from HBeAg positive human sera by the selective binding to polymerized human serum albumin. The HBsAg was eluted from agarose linked polymerized human serum albumin with 3M sodium thiocyanate. This allowed a 25 to 80-fold purification of the serum HBsAg. This procedure does not, however, allow the purification of recombinant derived pre-S(2)-HBsAg.